check.ErgmTerm: Ensures an Ergm Term and its Arguments Meet Appropriate Conditions

Description

Helper functions for implementing ergm() terms, to check whether the term can be used with the specified network. For information on ergm terms, see ergmTerm. ergm.checkargs, ergm.checkbipartite, and ergm.checkderected are helper functions for an old API and are deprecated. Use check.ErgmTerm.

Usage

check.ErgmTerm(
  nw,
  arglist,
  directed = NULL,
  bipartite = NULL,
  nonnegative = FALSE,
  varnames = NULL,
  vartypes = NULL,
  defaultvalues = list(),
  required = NULL,
  dep.inform = rep(FALSE, length(required)),
  dep.warn = rep(FALSE, length(required)),
  argexpr = NULL
)

Value

A list of the values for each possible argument of term X; user provided values are used when given, default values otherwise. The list also has an attr(,"missing") attribute containing a named logical vector indicating whether a particular argument had been set to its default. If argexpr= argument is provided, attr(,"exprs") attribute is also returned, containing expressions.

Arguments

nw: the network that term X is being checked against
arglist: the list of arguments for term X
directed: logical, whether term X requires a directed network; default=NULL
bipartite: whether term X requires a bipartite network (T or F); default=NULL
nonnegative: whether term X requires a network with only nonnegative weights; default=FALSE
varnames: the vector of names of the possible arguments for term X; default=NULL
vartypes: the vector of types of the possible arguments for term X, separated by commas; an empty string ("") or NA disables the check for that argument, and also see Details; default=NULL
defaultvalues: the list of default values for the possible arguments of term X; default=list()
required: the logical vector of whether each possible argument is required; default=NULL
dep.inform, dep.warn: a list of length equal to the number of arguments the term can take; if the corresponding element of the list is not FALSE, a message() or a warning() respectively will be issued if the user tries to pass it; if the element is a character string, it will be used as a suggestion for replacement.
argexpr: optional call typically obtained by calling substitute(arglist).

Details

The check.ErgmTerm function ensures for the InitErgmTerm.X function that the term X:

is applicable given the 'directed' and 'bipartite' attributes of the given network
is not applied to a directed bipartite network
has an appropiate number of arguments
has correct argument types if arguments where provided
has default values assigned if defaults are available

by halting execution if any of the first 3 criteria are not met.

As a convenience, if an argument is optional and its default is NULL, then NULL is assumed to be an acceptable argument type as well.